Wake Dynamics of a Cylinder with a Flexible Splitter Plate: An Experimental Study

As the world grapples with the challenges of global warming, there has been a significant push for the development of new methods of harnessing renewable energy. Energy harvesters have been a new avenue to generate electrical power locally for remote applications. An energy harvester is a device that taps into aeroelastic phenomena to convert...

Microphones as Airspeed Sensors for Micro Air Vehicles

This project proposes and evaluates a novel concept for an airspeed instrument aimed at small hybrid unmanned aerial vehicles. The working principle is to relate the power spectra of the wall-pressure fluctuations beneath the turbulent boundary layer formed over the vehicle’s body to its airspeed. The instrument consists of two microphones,...

Effect of N₂ and CO₂ bubbles on gas volume fraction and flow pattern in a quasi-2D bubble column by shadow imaging

This study reports the effect of N₂ and CO₂ bubbles on dilute to dense gas-liquid two-phase bubbly flow. A shadowgraph imaging technique captured bubble images at a high spatiotemporal resolution. The recordings of bubble images allow us to compute gas fraction distribution. It requires challenging segmentation and gas...

Microphones as Airspeed Sensors for Unmanned Aerial Vehicles

This paper puts forward a novel design for an airspeed instrument aimed at small fixed-wing tail-sitter unmanned aerial vehicles. The working principle is to relate the power spectra of the wall-pressure fluctuations beneath the turbulent boundary layer present over the vehicle’s body in flight to its airspeed. The instrument consists of two...

Modelling and Analysis of Atrial Epicardial Electrograms: An approach based on graph signal processing and confirmatory factor analysis

Atrial fibrillation (AF) is a frequently encountered cardiac arrhythmia characterized by rapid and irregular atrial activity, which increases the risk of strokes, heart failure and other heart-related complications. The mechanisms of AF are complicated. Although various mechanisms were proposed in previous research, the precise mechanisms of AF...

Fatigue Assessment of Steel Frames under Aerodynamic Loads: In Application to Steel Hollow Section Portal Frames Supporting Traffic Signs

Although modern technologies such as smartphones with GPS functionality make navigation substantially easier, automobilists still rely on traffic signs to inform them which exit to take or which lane to follow. These traffic signs on highways are of substantial size rendering them, and their support structures, extremely susceptible to...

Joint cardiac tissue conductivity and activation time estimation using confirmatory factor analysis

Mathematical models of the electrophysiology of cardiac tissue play an important role when studying heart rhythm disorders like atrial fibrillation. Model parameters such as conductivity, activation time, and anisotropy ratio are useful parameters to determine the arrhythmogenic substrate that causes abnormalities in the atrial tissue....

Cardiac tissue conductivity estimation using confirmatory factor analysis

Impaired electrical conduction has been shown to play an important role in the development of heart rhythm disorders. Being able to determine the conductivity is important to localize the arrhythmogenic substrate that causes abnormalities in atrial tissue. In this work, we present an algorithm to estimate the conductivity from epicardial...

Validation of aero-hydro-servo-elastic load and motion simulations in BHawC/OrcaFlex for the Hywind Scotland floating offshore wind farm

Climate change, as a result from global warming, requires an energy transition: the reduction of greenhouse gas emissions from fossil fuels and a radical innovation of the global energy system to proceed apace. Offshore wind is an important source of clean, renewable energy, and it plays a key role in the transition. 80% of the worldwide...

Disentangling stability and flexibility degrees in Parkinson's disease using a computational postural control model

Background: Impaired postural control in Parkinson's disease (PD) seriously compromises life quality. Although balance training improves mobility and postural stability, lack of quantitative studies on the neurophysiological mechanisms of balance training in PD impedes the development of patient-specific therapies. We evaluated the effects of...

Statistical Graph Signal Processing: Stationarity and Spectral Estimation

Stationarity is a cornerstone property that facilitates the analysis and processing of random signals in the time domain. Although time-varying signals are abundant in nature, in many contemporary applications the information of interest resides in more irregular domains that can be conveniently represented using a graph. This chapter reviews...

Combined Wind and Wave Loads for Fatigue Analysis in the Frequency Domain

Project Code: OE54015, OE54030. The potential of offshore wind is enormous. The wind resource offshore is generally much greater than onshore, especially at bigger water depths. Expanding prudently into the sea leads to bigger support structures for the wind turbine. Therefore, the need for optimized designs, which will establish the wind energy...

Determination of line edge roughness in low-dose top-down scanning electron microscopy images

We investigated the off-line metrology for line edge roughness (LER) determination by using the discrete power spectral density (PSD). The study specifically addresses low-dose scanning electron microscopy (SEM) images in order to reduce the acquisition time and the risk of resist shrinkage. The first attempts are based on optimized elliptic...

How to handle colored observation noise in large least-squares problems

An approach to handling colored observation noise in large least-squares (LS) problems is presented. The handling of colored noise is reduced to the problem of solving a Toeplitz system of linear equations. The colored noise is represented as an auto regressive moving-average (ARMA) process. Stability and invertability of the ARMA model allows...

Dynamics of gas-solids fluidized beds: Analysis of pressure fluctuations

Aircraft responses to atmospheric turbulence. A comparative study

The generation of equal probability design load conditions, using P.S.D.-techniques

A method is derived to generate consistent sets of design load conditions if aircraft design loads are determined using the Design Envelope criterion of the Power Spectral Density (P.S.D.)-method. The method is based on the use of the correlation coefficients between the various loads. Two sets of design load conditions have special properties...